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authorVladimir Oltean <olteanv@gmail.com>2019-08-25 21:32:12 +0300
committerDavid S. Miller <davem@davemloft.net>2019-08-27 20:31:12 -0700
commitbcccb0a535bb99616e4b992568371efab1ab14e8 (patch)
treece18c6dc616360102275569798204bf33144ab8b /net/dsa
parent94acaeb50ced653bfe2c4d8037c70b107af14124 (diff)
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net: dsa: tag_8021q: Future-proof the reserved fields in the custom VID
After witnessing the discussion in https://lkml.org/lkml/2019/8/14/151 w.r.t. ioctl extensibility, it became clear that such an issue might prevent that the 3 RSV bits inside the DSA 802.1Q tag might also suffer the same fate and be useless for further extension. So clearly specify that the reserved bits should currently be transmitted as zero and ignored on receive. The DSA tagger already does this (and has always did), and is the only known user so far (no Wireshark dissection plugin, etc). So there should be no incompatibility to speak of. Fixes: 0471dd429cea ("net: dsa: tag_8021q: Create a stable binary format") Signed-off-by: Vladimir Oltean <olteanv@gmail.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dsa')
-rw-r--r--net/dsa/tag_8021q.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/net/dsa/tag_8021q.c b/net/dsa/tag_8021q.c
index 6ebbd799c4eb..67a1bc635a7b 100644
--- a/net/dsa/tag_8021q.c
+++ b/net/dsa/tag_8021q.c
@@ -28,6 +28,7 @@
*
* RSV - VID[9]:
* To be used for further expansion of SWITCH_ID or for other purposes.
+ * Must be transmitted as zero and ignored on receive.
*
* SWITCH_ID - VID[8:6]:
* Index of switch within DSA tree. Must be between 0 and
@@ -35,6 +36,7 @@
*
* RSV - VID[5:4]:
* To be used for further expansion of PORT or for other purposes.
+ * Must be transmitted as zero and ignored on receive.
*
* PORT - VID[3:0]:
* Index of switch port. Must be between 0 and DSA_MAX_PORTS - 1.